Spatial heterogeneity of benthos on the Carolina continental slope: Large (100 km)-scale variation

Schaff, T, Levin L, Blair N, DeMaster D, Pope R, Boehme S.  1992.  Spatial heterogeneity of benthos on the Carolina continental slope: Large (100 km)-scale variation. Marine ecology progress series. Oldendorf. 88:143-160.


abundance, ANW, USA, North Carolina, ANW, USA, South Carolina, ASFA 1: Biological Sciences & Living Resources, continental slope, correlation, marine, microorganisms, O 1070:Ecology/Community Studies, Oceanic Abstracts, organic carbon, particulate flux, phytobenthos, Q1 01462:Benthos, spatial distribution


Large-scale spatial heterogeneity of macrofaunal and microbial communities was examined on the continental slope off North and South Carolina, USA, by comparing 3 sites, separated by 130 to 150 km and all at 850 m water depth. Significant variation was found among macrofaunal assemblages at all 3 sites, and between microbial counts at 2 sites. We investigated the hypothesis that 100 km scale heterogeneity was driven by variation in organic C flux to the sea floor. The northernmost site (Site III, off Cape Hatteras, NC) was found to have macrofaunal abundances (> 55,000 m super(-2)) higher than any previously recorded from this depth, and significantly higher than those at Site II (off Cape Lookout, NC) (21,319 m super(-2)) or Site I (off Charleston, SC) (9438 m super(-2)). Trends in macrofaunal abundance did not follow those of sediment TOC (total organic carbon), but agreed well with estimates of total carbon flux for the 3 sites. Mixing coefficients determined from profiles of naturally occurring super(234)Th (half life 24 d) indicate that the sediments at Site III are mixed 2 to 6 times faster than at the other 2 sites, which is consistent with the trends in macrofaunal abundance and biomass.